Sensors are known from the prior art for measuring the force exerted by a biological cell. For example, DE 10 2011 050 493 A1 discloses a cell force sensor, which comprises a plurality of elastic elements, which are in each case fastened at the lower end thereof on a substrate and have an upper free end. The deflection of the elastic elements is ascertained on the basis of a diffraction image. However, a sensor of this type necessitates a structure with elastic elements, which can only be produced with increased outlay in an individual case.
Furthermore, a system for detecting the presence of an analyte is described in US 2005/0068543 A1. In this case, two grids are provided, arranged above one another in an offset manner. An identifying material for the analyte is arranged on one of the grids. The identifying material binds the analyte to it. When the analyte is bound to the grid, the optical depth of the modulation by the grid changes. However, this construction is not suitable for investigating a transient behaviour, such as for example a movement of biological cells, with small temporal resolution.
It is specifically the detection of the movement and (population) growth of biological cells that is desirable however for improved diagnostics, for example of cancer illnesses. Cancer illnesses are currently the second leading cause of death. By 2030, according to the American Cancer Society, the number of global cancer illnesses shall almost double again. The movability of cells, called cell motility in specialist circles, is an important indicator, among others, in wound healing, immune response, angiogenesis and in many illness-related changes, particularly metastasis in the case of cancer. Automatic measurement of cell motility is therefore of great importance for developing medical active agents.
Hitherto, methods were used for assessing cell motility, which are based on an image analysis of movement sequences of individual cells and determination of the average quadratic displacement of the cell per unit time. Cells are often investigated in 3D hydrogels, which constitute an artificial tissue matrix. These methods are cost- and time-intensive however, particularly if a larger number of cells should be observed for a statistical analysis.